Endodontic treatment may be one of the most challenging of the dental disciplines. Root canals systems (RCS) are extremely complex and highly variable within the human population. Microbiologic techniques to date have identified over 750 different bacteria involved in the development of apical periodontitis. However, at electron microscopic levels of inspection, modern endodontic treatment protocols are crude at best. Cleaning and shaping, while significantly reducing bacterial burden, cannot alone render a RCS sterile. Chemical treatment with NaOCL and EDTA are critical to disinfection of the RCS, removing bacteria from the canal recesses unavailable to mechanical instrumentation. And yet, even with the most rigorous of techniques, materials and obsessive- compulsive operators, we still have endodontically treated teeth which show clinical and radiographic signs of infection.
Confronted with a failing endodontic result, the dentist and patient are faced with one of three choices: endodontic retreatment, apical surgery, or extraction and prosthetic decisions (fixed or removable partial dentures, implant based crowns, empty spaces). None of the options, with the exception of extraction without prosthetic replacement, can guarantee the patient be infection-free five or more years down the road.
As dental health professionals, our most important role may be as teachers and guides to help our patients understand and evaluate the options available to them. To do this adequately, we must have available to us high quality research which limits confounding factors, as well as researcher error and bias.
In an article published in the May 2012 issue of the Journal of Endodontics (JOE 38:5 pp 570-579), Dr. Shimon Friedman of the University of Toronto and colleagues at the University of Bern, Switzerland, set out to clarify the five-year outcomes we can expect from apical surgery of endodontically treated teeth with chronic apical periodontitis (CAP).
The surgical phase of this double-blind, prospective study involved 194 teeth with CAP. One operator performed all of the surgical treatment using modern microsurgical techniques. All teeth were sound restoratively healthy from a periodontal perspective. All surgical treatment was done with enhanced magnification and lighting with a surgical endoscope, root ends were reduced 3mm perpendicular to the long axis of the root, and apical class I root-end preparations were made with diamond ultrasonic root-end tips in the vertical axis of the canal, including preparation of the isthmus connecting major canals. The root ends were sealed with either MTA, Super-EBA (a fortified IRM), or a bonded composite resin.
191 surgically treated teeth were available for radiographic and clinical evaluation at one year with a healing rate of 84% (160/191). Phase II of the study looked at the healing rate at a five-year follow-up. Five years after apical surgery, 170 teeth were evaluated. 21 teeth were either extracted (11 vertical root fractures, one prosthetic failure) or did not return for follow-up (nine teeth). A recall rate of 89% is remarkable and greatly legitimizes the obtained results.
76.5% (130/170) of the teeth evaluated were considered as healed (complete osseous healing of lesion and no clinical signs or symptoms). 6.5% (11/170) were considered as incompletely healed (some radiolucency present with no clinical signs or symptoms) and 17% (29/170) considered as uncertain or unsatisfactory healing. Significant differences were found among the root-end filling groups. MTA showed the best five-year healing at 86%, composite filling 75%, and Super-EBA showed the poorest result at 67%. At the one-year follow-up, MTA had a 91% healed rate with a 5% regression over the next four years. Friedman’s results showing an 86% healing of apical surgery with MTA as the root end filling material (used in our office exclusively since 1995) are consistent with previous, though less rigorous studies in the literature.
As you guide your patient through the options available to them, you can be quite confident in quoting this number (86%) for apical surgery. However, a number of factors may move this success rate one way or another. Tooth location, patient compliance factors, adequacy of coronal restoration and endodontic root fill – to name just a few – may affect the outcomes and treatment pathway you and your patients choose.
ABOUT DR. HOWARD BITTNER
Dr. Bittner was born and raised in the Surrey/Langley area. Following his pre-dental training at Simon Fraser University, he received his Doctor of Dental Medicine from the University of British Columbia in 1982 and his Certificate in Advanced Graduate Studies in Endodontics from Boston University’s Goldman School of Dental Medicine in 1995.
Dr. Bittner was in private practice in general dentistry for 11 years in Langley prior to his endodontic specialty training. He has a wide background in all facets of general dentistry, with advanced dental training in prosthetic dentistry from respected educational facilities such as Creating Restorative Excellence in Tacoma, Washington, and The Pankey Institute in Miami, Florida. He has been practicing the dental specialty of Endodontics since 1995.
He is a past president of the British Columbia Society of Endodontists, the Dental Specialists Society of British Columbia, and the Concentric Endodontic Study Club. Dr. Bittner is also a guest lecturer in the Faculty of Dentistry at the University of British Columbia.